Health Talk

Hearing Loss May Speed Up Dementia

Here’s a really good reason to get your hearing tested: New research indicates that older Americans with untreated hearing loss experience a faster decline in thinking and memory skills than do those with normal hearing.

The study has widespread ramifications, considering that hearing loss affects 30 percent of adults ages 65 to 74, and 47 percent of adults 75 or older, according to the National Institutes of Health (NIH). At the same time, only 25 to 29 percent of those 70 or older use hearing aids.

In the study of 1,984 older adults (average age: 77), those with measurable hearing loss had a 30 to 40 percent greater cognitive decline after six years when compared with their counterparts who did not have hearing loss. That difference translated to a 24 percent increased risk of cognitive impairment among those with hearing loss, according to lead study author Frank Lin, M.D., of the Johns Hopkins Center on Aging and Health.

Those with the most severe hearing loss also had the greatest mental decline and the highest likelihood of developing it, Lin and his colleagues wrote. Cognitive problems, however, were evident even in subjects who had mild hearing loss, like having trouble following a conversation in a busy restaurant, Lin told USA Today. The study, funded by the NIH, was published in JAMA Internal Medicine online this week.

While the scientists didn’t determine why mental skills decline when hearing loss occurs, Lin said there are various theories. It could be that the same mechanism in the brain that causes cognitive impairment also affects hearing function. Another possibility is that the effort to hear and understand muffled sounds causes problems in the brain. Finally, it simply could be the social isolation of not being able to hear well that impacts brain function. Or, it could be a combination of all three reasons.

And it’s not just older people whose thinking abilities are affected when their hearing diminishes. “Otherwise healthy young adults” with hearing loss are similarly affected, Arthur Wingfield, professor of neuroscience at Brandeis University, told USA Today.

Wingfield was not involved with Lin’s research, but, as he told the newspaper, the “link Dr. Lin demonstrates between mild loss of hearing and cognitive skills is a call for alertness to a public health issue that has received less attention than it should.”